mintty character cell "detritus"

Fri Sep 26 17:21:30 GMT 2025

On 9/25/2025 23:03, Thomas Wolff via Cygwin wrote:
>> Am 26.09.2025 um 07:33 schrieb Jim Garrison via Cygwin:
>> This is a very minor and totally cosmetic issue, but it's been around 
>> "forever" so I'm curious if I'm the only one seeing it.
>>>> When displaying colored text in mintty configured with a block cursor 
>> and dark background, as the cursor moves across text (in vi, say) it 
>> will change the color of the rightmost pixel column of certain 
>> characters (not all).  This happens when moving the cursor left-to- 
>> right, and the discolored bits disappear (or go back to their original 
>> color) when moving right-to-left.
>>>> I'm pretty sure this has to do with anti-aliasing, and may not even be 
>> mintty's problem, but I've never seen it anywhere else.
>>>> I put a couple of small demonstration screenshots on Google Drive:
>>>> Actual size: https://drive.google.com/file/ 
>> d/1gF86FJMJqQJDaFHTVZXEZrMNIyRtTCSL/view?usp=sharing
>>>> Enlarged view: https://drive.google.com/file/ 
>> d/15zWPNZQvryILvqRhaiFE3O35L057R8jQ/view?usp=sharing
>>> Is this effect affected by the Font smooting setting?
>
Good catch! Changing Font-Smoothing to Partial or None greatly reduces 
the problem but it doesn't go away completely. After further 
experimentation I find that it also depends on the font.
I tried a few:
Affected: 	Lucida Console, Courier, Cascadia Code
Not affected: 	Lucida Sans Typewriter, Consolas, Brougham
The "Not affected" fonts don't display the problem with any 
font-smoothing setting, while for the affected fonts the problem is 
still present but affects fewer characters with font-smoothing None or 
Partial.
[Also, I got the directions backwards in my original message. The issue 
occurs when moving the cursor R-to-L, and "corrects" when moving L-to-R.]
-- 
Jim Garrison
jhg@acm.org